Bauxite
Bauxitealso called alumina , aluminum content is above 40% , Main ingredient is alumina,white or grey color , will become brown yellow or pale red for iron content. on the current market the density of bauxit is about 2.4-3.5 g/cm3, hardness is 1 ~ 3, opaque . Very difficult to melt , Insoluble in water, can be soluble by sulfuric acid, sodium hydroxide . Mainly used for smelting aluminum , refractory materials.
Calcined bauxite is one of the principal ore of aluminum. Calcined bauxite contains hydrous aluminum oxides and aluminum hydroxides, formed through the laterization of aluminous rocks in tropical and subtropical areas .calcined bauxite is obtained by calcining (heating)superior grade bauxite at high temperature (from 850℃ to 1600℃) .this process removes moisture thereby increasing the alumina content. compared to an alumina content of about 57% to 58% in raw bauxite, calcined bauxite has an alumina content of 84% to 88%.the heating is carried out in rotary kilns.
Calcined bauxide specification:
| Grade | Al2O3 | Fe2O3 | TiO2 | K2O+Na2O | CaO+MgO | Bulk density |
| 75 | 75min | ≤3.0 | ≤4.0 | ≤0.3 | ≤0.5 | ≥2.70 |
| 80 | 80min | ≤3.0 | ≤4.0 | ≤0.3 | ≤0.5 | ≥2.80 |
| 85 | 85min | ≤2.0 | ≤4.0 | ≤0.3 | ≤0.5 | ≥3.00 |
| 86 | 86min | ≤2.0 | ≤4.0 | ≤0.3 | ≤0.5 | ≥3.10 |
| 87 | 87min | ≤2.0 | ≤4.0 | ≤0.3 | ≤0.5 | ≥3.20 |
| 88 | 88min | ≤1.8 | ≤4.0 | ≤0.25 | ≤0.5 | ≥3.25 |
| 90 | 90min | ≤1.8 | ≤4.0 | ≤0.25 | ≤0.5 | ≥3.30 |
Applications:calcined bauxite is typically calssified according to its intended commercial application,such as abrasive ,cement ,chemical, metallurgical, and refractory .as raw material for use in high alumina and super duty refratory bricks and shapes ,plastics ,castable refratory, motors, gun mixes, ramming mixes, abrasive grains and other products.